#4. Zack Ryder
Zack Ryder is someone else who at one point was incredibly popular in the WWE and has just been flat-out underused since the height of that popularity was killed off. Plus he's known to be good friends with Cody so he's been heavily linked with AEW.
However, Ryder leaving WWE would be a huge mistake. He currently has his show with Curt Hawkins about collectable wrestling figures and he's just reunited with his former tag-team partner as an official tag-team.
If Ryder were to leave WWE for AEW he'd lose the show he gets to do and he'd be depriving the WWE Universe of one of the longest running storyline conclusions and potential greatest WWE moment ever - Curt Hawkins (and himself) finally winning a match.